Assessment of the effect of short-term weathering on the molecular-level chemical composition of crude oils in contact with aquatic environments.

Multiple studies have focused on the effect of long-term weathering processes on oils after spill events, without considering the chemical compositional changes occurring shortly after the release of oil into the environment. Therefore, the present study provides a broad chemical characterization for understanding of the changes occurring in the chemical compositions of intermediate (°API = 27.0) and heavy (°API = 20.9) oils from the Sergipe-Alagoas basin submitted to two simulated situations, one under marine conditions and the other in a riverine environment. Samples of the oils were collected during the first 72 h of contact with the simulated environments, followed by evaluation of their chemical compositions. SARA fractionation was used to isolate the resins, which were characterized at the molecular level by UHRMS. The evaporation process was highlighted, with the GC-FID chromatographic profiles showing the disappearance of compounds from n-C10 until n-C16, as well as changes in the weathering indexes and pristane + n-C17/phytane + n-C18 ratios for the crude oils submitted to the riverine conditions. Analysis of the resins fraction showed that basic polar compounds underwent little or no alterations during the early stages of weathering. The marine environment was shown to be much less oxidative than the riverine environment. For both environments, a feature highlighted was an increase of acidic oxygenated compounds with the increase of weathering, especially for the crude oil with °API = 27.0.

Trends and challenges in analytical chemistry for multi-analysis of illicit drugs employing wastewater-based epidemiology.

Wastewater-based epidemiology (WBE) for quantification of illicit drug biomarkers (IDBs) in wastewater samples is an effective tool that can provide information about drug consumption. The most commonly quantified IDBs belong to different chemical classes, including cocaine, amphetamine-type stimulants, opioids, and cannabinoids, so the different chemical properties of these molecules pose a challenge in the development of analytical methods for multi-analyte analysis. Recent workflows include the steps of sampling and storage, sample preparation using solid-phase extraction (SPE) or without extraction, and quantification of analytes employing gas or liquid chromatography coupled with mass spectrometry. The greatest difficulty is due to the fact that wastewater samples are complex chemical mixtures containing analytes with different chemical properties, often present at low concentrations. Therefore, in the development of analytical methods, there is the need to simplify and optimize the analytical workflows, reducing associated uncertainties, analysis times, and costs. The present work provides a critical bibliographic survey of studies published from the year 2020 until now, highlighting the challenges and trends of published analytical workflows for the multi-analysis of IDBs in wastewater samples, considering sampling and sample preparation, method validation, and analytical techniques.

Rapid and direct detection of artificially aged papers employing easy ambient sonic-spray ionization mass spectrometry.

RATIONALE: The effort to make fake documents look real leads to the use of crickets and beverages to produce artificially aged papers, as land titles, based on yellowing caused by the use of these methods. An old practice in Brazil, called "cricketing", has led to the misappropriation of Brazilian land using these documents. We propose a rapid, simple, instantaneous and non-destructive method to identify artificially aged papers by easy ambient sonic-spray ionization mass spectrometry (EASI-MS) analysis. METHODS: Three typical aging procedures were used to obtain artificially aged papers using coffee, cola drink, and crickets, with the papers being analyzed by EASI-MS. Multivariate statistical analyses were performed on the data to find the sample groups and to study the most relevant ions of each ageing procedure. High-resolution MS (HRMS) was used to obtain the exact masses and attribute formulae to relevant ions present in the samples. RESULTS: The combination of EASI-MS and multivariate statistical analyses allowed us to identify the most relevant ions to classify the adulteration of documents and HRMS identified most of these relevant ions. TMS fingerprinting in combination with multivariate analysis also demonstrated that this approach can qualitatively differentiate all the examined paper samples. CONCLUSIONS: We developed a cheap, fast and easy method that can help to elucidate counterfeit documents that have been artificially aged, helping to identify chemical additives and one that can be used in forensic laboratories.

Characterization of the lipid profile from coconut (Cocos nucifera L.) oil of different varieties by electrospray ionization mass spectrometry associated with principal component analysis and independent component analysis.

Coconut oil (CO) from fifteen different varieties of coconuts (Cocos nucifera L.) and one CO processed on an industrial scale were analyzed by electrospray ionization mass spectrometry (ESI-MS) and the data processed using the chemometric tools principal component analysis and independent component analysis. ESI-MS fingerprinting of lipid compounds showed predominance of diacylglycerols and triacylglycerols, as confirmed by high-resolution MS measurements. Chemometric processing of the ESI-MS data differentiated the coconut oil samples, showing that different coconut varieties/cultivars produce oils with distinguishable abundances of lipidic compounds. Thus ESI-MS analysis followed by data treatment using chemometric tools offers a tool able to classify the industrial coconut oils in a fast, simple and effective way, as well as serving as a potential method to identify the coconut varieties by the CO origin, and the occurrence of any adulteration. The procedure may also be applied for quality control of the industrial processes.

Forensic Application of X-ray Fluorescence Spectroscopy for the Discrimination of Authentic and Counterfeit Revenue Stamps.

Energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy with data treatment via chemometric tools was explored as an analytical protocol to discriminate between authentic and counterfeit revenue stamps. Untreated samples were directly analyzed, and the discrimination was based on the characterization of constituent elements present in the inks and paper. Authentic samples and samples that were suspected of being counterfeit were analyzed at three different areas on their surfaces: the ink-printed area, the non-printed area, and the holographic area. Principal component analysis (PCA) was applied to the data to discriminate between authentic and counterfeit revenue stamps. Major differences in the elemental composition were noted (according to chemometrics and t-test, p < 0.05), and ED-XRF spectroscopy plus PCA protocol is proposed for use by non-specialist operators to screen for counterfeit stamps.

Subcritical extraction of flaxseed oil with n-propane: Composition and purity.

Flaxseed (Linum usitatissimum L.) oil was obtained via subcritical n-propane fluid extraction (SubFE) under different temperatures and pressures with an average yield of 28% and its composition, purity and oxidative stability were compared to oils obtained via conventional solvent extraction methods (SEMs). When the oxidative stability was measured by differential scanning calorimetry, the oil was found to be up to 5 times more resistant to lipid oxidation as compared to the SEM oils. Direct infusion electrospray ionization mass spectrometry (ESI-MS) analysis showed characteristic and similar TAG profiles for SubFE and SEMs oils but higher purity for the SubFE oil. The flaxseed oil content of ß-tocopherol, campesterol, stigmasterol and sitosterol were quantified via GC-MS. SubFE showed to be a promising alternative to conventional SEM since SubFE provides an oil with higher purity and higher oxidation stability and with comparable levels of biologically active components.

Characterization of ANFO explosive by high accuracy ESI(±)-FTMS with forensic identification on real samples by EASI(-)-MS.

Ammonium nitrate fuel oil (ANFO) is an explosive used in many civil applications. In Brazil, ANFO has unfortunately also been used in criminal attacks, mainly in automated teller machine (ATM) explosions. In this paper, we describe a detailed characterization of the ANFO composition and its two main constituents (diesel and a nitrate explosive) using high resolution and accuracy mass spectrometry performed on an FT-ICR-mass spectrometer with electrospray ionization (ESI(±)-FTMS) in both the positive and negative ion modes. Via ESI(-)-MS, an ion marker for ANFO was characterized. Using a direct and simple ambient desorption/ionization technique, i.e., easy ambient sonic-spray ionization mass spectrometry (EASI-MS), in a simpler, lower accuracy but robust single quadrupole mass spectrometer, the ANFO ion marker was directly detected from the surface of banknotes collected from ATM explosion theft.